Mixing apparatus and method for mixing fluids

An apparatus for mixing at least two fluids, wherein the apparatus comprises two confronting surfaces (1, 2), spaced by a distance (7),

• wherein the first surface (1) contains at least three cavities (3), wherein at least one of the cavities has a depth (9) relative to the surface (1),
• wherein the second surface (2) contains at least three cavities (4) wherein at least one of the cavities has a depth (10) relative to the surface (2),
• wherein the cross-sectional area for flow of the liquid available during passage through the apparatus successively increases and decreases at least 3 times, and
• wherein the surface (1) has a length (5) between two cavities, and
• wherein the surface (2) has a length (6) between two cavities, and
• wherein the surfaces (1, 2) are positioned such that the corresponding lengths (5, 6) overlap to create a slit having a length (8) or do not overlap creating a length (81),
• wherein the cavities are arranged such that the cross-sectional area for flow of the liquid available during passage through the apparatus successively increases in the cavities and decreases in the slits by a factor of at least 3, and
• wherein the distance (7) between the two surfaces (1,2) is between 3 micrometers and 300 micrometers,
• characterised in that
• either the ratio between the length (8) and the distance (7) between the two surfaces (1, 2) ranges from 0 to 10,
• or wherein the length (81) of overlap between the two surfaces (1, 2) is less than 600 micrometers.